|
|
Electrochemical Analysis of Chemically Modified DNA at Gold Electrodes
Vidláková, Pavlína ; Havran, Luděk ; Fojta, Miroslav
DNA labeling is used to increase sensitivity of its electrochemical detection. Covalently bound markers based on a complex of osmium tetroxide with 22-bipyridine(Os,bipy) is one of those frequently applied. Os bipy reacts with pyrimidines (mainly thymines) in single stranded regions of DNA, therefore it represents a useful marker for the analysis of DNA structure or labeling of hybridization probes . Another possibility of DNA labeling is the incorporation of chemically modified dNTPs into DNA molecules with using primer extension. DNA labeling in connection with voltammetry at gold electrodes has application potential in development of sensors for studying of DNA structure and interaction.
|
|
|
Synthetic Biology Introduces New Base Pairs to Analyze
Špaček, Jan
An unnatural base pair is composed of two nucleobase analogues which specifically Pair only with each other similarly as natural DNA pairs do. Goal of the search for new base pair is expansion of genetic alphabet with new codons containing unnatural bases. Expanded genetic alphabet am, other things allows simultaneous site specific incorporation of non-standard amino acids into proteins Recently unnatural bases forming pairs vie hydrophobic interactions, which can be replicated by prokaryotic cells with efficiency and mutation rate similar to natural base pairs, have been shown. Synthetic biology provides new opportunities for application of electrochemical analysis.
|
|
|
Electrochemical Analysis of Carrageenans. The Effect of Acetate Concentration
Kos, S.S. ; Paleček, Emil
kappa-, iota-, and lambda-carrageenans are polysaccharides (PSs) which produce electrocatalytic chronopotentiometric peak H-ps in acetate buffer (pH 5.2) on the hanging mercury drop electrode (HMDE). Here we show that this peak (E-p1.8V) increases with the acetate concentration Using a. c. voltammetry we found that the appearance and the observed increase of peak H-PS is accompanied by a decrease of capacitive current below the background elecnolyte around1.8 V, suggesting strong adsorption of the negatively charged PS at the negatively charged HMDE. Compared to carrageenany dextran did not produce peak H-PS and did not strongly adsorb at negatively charged electrode.
|
|
| |
|
|
Constant Current Chronopotentiometry as a Method for Detection of Singlet Oxygen Protein Damage
Ostatná, Veronika ; Vargová, Veronika ; Černocká, Hana ; Paleček, Emil
Proteins are one of the major targets for oxidative damage in the cell.Indirect non-radical oxidation of the protein via formation and subsequent reaction with single oxygen (O-1(2))is one of the major processes.In this work we studied the single oxygen(O-1(2))-mediated oxidation of bovine serum albumin (BSA) by constant current chronopotentiometry in combination with mercury electrode.Our chronopotentiometric data show that photo-oxidized BSA was more susceptible to the electric field-induced denaturation than non-oxidized native BSA. Our method utilizing intrinsic electrochemical signal of proteins provides a sensitive detection methods for minor damages in various proteins.
|
|
|
New Ligands for Modification of DNA by Osmium Tetroxide Reagents
Havran, Luděk ; Zenka, Martin ; Fojta, Miroslav
Besides DNA intrinsic electroactivity, modification of DNA by redox active tags find wide use in electrochemical analysis of DNA interactions and damage. Application of these tags can improve specificity of the analysis. One from utilized labels in this field are complexes of osmium tetroxide with nitrogen ligands, which produce with DNA electroactive covalent adducts. These complexes preferentially react with thymine in single strand DNA. Type of used ligand influence electrochemical behavior forming adducts. In this contribution will be presented results which are acquired by testing of set a new ligands based of quinone and substituted 1, 10-phenanthroline.
|
|
| |
|
|
Analysis of Denatured PCR Products Modified with 7-deazapurine Bases at Hanging Mercury Drop Electrode
Dudová, Zdenka ; Špaček, Jan ; Havran, Luděk ; Pivoňková, Hana ; Fojta, Miroslav
7-deazapunines are synthetic analogues of natural purine nucleobases which can pair with pyrimidines, retaining pairing complementarity of their parent purines. There is replaced N7 atom by CH group in 7-deazapurines so that DNA modified with them don't participate in Hoogsteen basepairing and don't form alternative structures. Here is a study of 7-deazapurines incorpotated into DNA measured at HMDE by CV and ACV. While 7-deazaadenine was reduced at the HMDE, giving rise to a similar irreversible cathodic peak as the natural adenine, 7-deazaguanine didn't yield any peak analogous to the peak G due to Guanine, in Agreement with a loss of corresponding redox in 7-deazaguanine.
|
|
|
Amalgam Electrodes Pretreatment and Electrochemical Analysis of DNA
Daňhel, Aleš ; Fojta, Miroslav
Mercury meniscus silver solid amalgam electode (m-AgSAE) represents the most suitable and perspective alternative to mercury electrodes which excel in sensitivity to biopolymers and their structural changes. This work briefly summarizes factors influencing electrochemical analysis of DNA at mercury and amalgam electrodes and it is mainly devoted to development of suitable pretreatment procedure, which could securte repeatable and reliable measurements of DNA at m-AgSAes. The results are essential for further utilization of amalgam electrodes in developement of biosensors, since DNA samples are very strongly adsorbed at the electrodes, and none pretreatment procedure was found to be successful in their complete desorption.
|
|
|
Mobilization of neutral compounds by inorganic and small organic ions in capillary electrophoresis
Křížek, T. ; Martínková, E. ; Kubíčková, A. ; Hladílková, Jana ; Coufal, P. ; Heyda, J. ; Jungwirth, Pavel
The present study shows that neutral low-molecular-mass compounds that are presumed to possess zero electrophoretic mobility and are thus used as markers of electroosmotic flow in capillary electrophoresis can acquire electrophoretic mobility due to ion-specific interactions with constituents of background electrolyte. Therefore, these neutral markers, such as thiourea or dimethyl sulfoxide, can be separated in electric field and their migration order can vary depending on background electrolyte composition. This observation has some important implications for analytical and physico-chemical measurements using capillary electrophoresis because the choice of the marker-background electrolyte combination can influence the results of the measurement.
|
guest ::
